The field of the present invention is the construction of perpendicularly joined structures comprised of thin-walled plates and thin-walled tubes.
Typically, joint structures used in assembling thin-walled tubes and thin-walled plates have employed tapered tube joints or welded joints. With welded joints, either lap joints or the end of the thin-walled tube is flared or brazed joints are typically used. In the fabrication of mufflers where light weight and high vibration resistance are required, TIG auto welds are typically employed. Reference is made to FIG. 6 where thin-walled tubes 6 comprising an inlet tube I.sub.F and a funnel joint, tube J.sub.U are associated with a front end plate C.sub.F. The barrel of the muffler is typically joined with the end plate using the joining method of a lock seamed roll joint S.
FIG. 7 illustrates another joint technique for a sheet and tubes. A collar 01 has a first flange 02 extending outwardly and a second flange 04 extending inwardly. These flanges 02 and 04 are spaced apart. The collar 01 is positioned over the end 05A of a tube 05. The flange area 04 extends over the end 05A. A sheet 06 with an appropriately sized hole therethrough may then be positioned over the end 05A of the pipe 05 and the collar 01 so as to be held by the flange 02. The flange 04 may then be deformed with the end 05A of the tube 05 by being flared outwardly to retain the sheet 06. A second tube may then be joined with the assembly.
It is also known to join a thin-walled tube with a thin-walled plate by providing a hole in the plate with a cylindrical flange extending perpendicularly thereto. A lip on the end of the cylindrical flange extends radially inwardly and a thin-walled tube extends through the flange to abut against the lip. The assembly is then flared such that the lip, the end of the tube and the cylindrical flange are forced outwardly. This operation locks the tube axially to the plate. To form an assembly, the other end of the tube of reduced diameter may be positioned in the opening of another such assembly and welded in place.
Certain of the foregoing practices are disadvantageous in the manufacture and performance of such thin-walled assemblies. The welding of such thin-walled members can develop strain. Further, anticorrosion characteristics may be lessened by the heat of welding. Additionally, more highly skilled labor is required and the environmental impact of welding is experienced. Using the technique employing the collar 01, additional components are required and the joint strength is not great. Sheer torque and vibration on such joints can result in a loosening of the joint with consequential losses in sealing.